This section outlines the requirements for various function types.
UDF requirements
Each user-defined function (UDF) must meet several requirements.
User-Defined Aggregate Functions
To write an aggregate function, you must have a place to store your data between invocations. For example, if you write your own "SUM()" function, you must store the subtotal from the previous calls to the function and then add the new value from the current call to the function.
XML Signatures
Sybase CEP software requires the description of the UDF to be in an XML file, which is put in the plugins directory of both the server and Studio.